Alloy steel



C. H. WILLS Feb. 26 1935.

ALLOY STEEL 4; SheetS-Sheet 1 Fi led Ju1y 17, 1954 IOOOX G; menfife Pe m'llfe ZISOX INVENTOR dflmd/ 17/150 I BY v ATTORNEYS Feb. 2 1935..

H airdness C. H. WILLS ALLOY STEEL Specimens Ouefic/rad/n Wafer Harden/7 9 6min Tkmperdfurc Size 1400f 7-5 4500 7-8 I woo 7-8 1700 7-5 .1 0 .I D/sfance From Cenfer-hrches INVENTOR xwm ATTORNEYS Feb. 26 1935. c. H. WILLS ,90

ALLOY STEEL I Filed July 17, 1934 4 Sheets'Sheet 4 Specimens quenched In Wafer Rock will 56 Ifc Hdrdness -.a -.z' o- .l .2, .3 Dlsfance From Gamer-Inches %2 ATTOIQI QEYJ economicai rh sus res-26,1935.

v U Nirsn STATES gsurnames:-

'- ALLOY 'srssa.

onus n li wma ma. Application July 17, 1934, Serial No. 135.545

1 'zs-aii What I mean by general purpose steel" may be illustrated by reference to the automobile.

My steel, for example; is suitable for axles, cranksh'afts, connecting rods, torsion members such as shafts, transmission gears, pinions and ring gears, valves, and springs, coiled or flat.

isalso useful for large pie ce's,'such as die blocks, piston rods for-hammers and locomotives, and the like. My'steel is also useful for parts formed from sheet and strip steel, such as braces,brack'-- ets and frame members for automobiles, railroad rolling equipment and general structural work. Also for plates, shipplates and deck-plates; for I-beams, channels and similar structural mem-. here: for rail and angle bars. It isuseful for I stampings such as kitchen utensils, sinks, lava- 'tories, bath tubs etc., especially when coated with ceramic enamel;

Mysteel is useful for tubes for various purpom such as axles, bearings and structural -members.

= My steel may be effectively heat treated and by heat treatment. I include not only quenching and drawingoperations but also annealing and .nor

malizing or air blastor other cooling.

steel of myinvention has very much increasedductility and toughness and resistance to shock and fatigue above average steels of specific analysiaemployed for parts such as above ,set forth; and these characteristics can be obtained by the regular processing operations; of heat treatment such as quenching and drawing, normalizing, etc., withouiii' special equipment other than that ordinarily used.

In carrying out my invention I deliberately make the steel abnormal, the extent of the departure from normality being dependent upon appear.

the particular use'to which the finished piece is to be put. In nocase however; should the abnormality becarried to the point where the ends of my invention I am fully aware that abnormality in steels is known as are many .of the factors. or conditions which win produce abnormality: Heretofore, however, abnormality has been generally avoided as rendering the steel unfit. Some of the re therefor are that abnormality has a mark;

to manufacture and effects additional;

- range in the takes place in such'a'manner that the steel ten acreage wiu further tendency. to 'decrease the extent of depth hard ening, produces soft spots in quenching, lowers the ability to carburize readily, etc.

I have discovered that abnormality together with molybdenum plays a very important part in securing the improved results obtained in my steel. Ibelieve that this is due to the fact that during the transition period through the critical enching operation, the transiti n to pass from austenite to 'a mild martensite o even-directly to troostite, without-the production of the very' hard and large amounts.

of brittle martensite present when' ordinary or regular steel of the normal condition is quenched? and which, in the normal steel, has the effect of causing,- or the tendency to cause, martensitic fracture or ov'erstrain, which cannot be sufficiently removed by the subsequent drawing operations. In steel, therefore, martensitic. fracture or over-strain, if not entirely eliminated, is at least minimized to the point where the improved properties of increased ductility,- toughness andlresistance 'to. shock and fatigue. are obtained.'. 4

Another contributing factor is fine grain-size, say from #5 to #8or finer, of the A. S.'T.1M.v

standardchart. I prefer a grain size, of from 6 to 8. Fine grain size, as does the abnormality, tends to decrease the depth of. penetration of hardening. This otherwise objectionable char-' acteristic, I overcome as will later be described. 7

I have found that a molybdenum steel which is made abnormal and whichhas' flnegrain size gives the remarkable results herein set forth. By

control of the degree of abnormality and by maintaining proper balance of the elements in the steel, I flnd that I can get a steel of the improved 'hereinbefore mentioned, which has the needed for the particular use to which For example, 'I can, in

properties properties the piece is to be put.

'both small and large pieces, obtain uniform hard-- nes's from the surface to the middle; or I can produce apiece hard at the surface and shading ed to a soft but tough core.

An abnrmal steel may be. readily recognized andfor the. of this specification it will suffice to say that an abnormal steel is one in hich the physical condition, as seen by microscopic examina'jflon after carburizing and cooling (McQuaid-Ehn'test) is acondition -of divorced cementite of greater or less degree. The three around the pearlite in such a manner that-the original grain borders are not distinct. This structure is thus different from the so-called normal steels which. under the McQuaid-Ehmtest show distinctly formed grains-with sharply out.- lir'iedbolders.

nstituents generally. pearlite, cementite and ferrite, the-latter two more or less For purposes of. illustration a normal steel is shown in Figure l and a molybdenum containing abnormal steel of my invention in Figure 2 of the accompanying drawings.

I have found that by adding molybdenum I can overcome or counteract the tendency of abnormality and of small grain size to decrease the depth of hardness, and secure any extent of depth hardness desired. I vary the degree of abnormality'and the amount of molybdenum, depfendent upon the size of'the article to be heat treated and upon the results desired. I also vary the quantity 7 of the other constituents which are preferably earbon, manganese and silicon. This,';togeth'er with the control of abnormality and of the molyb-.

denum, makes it possible that manufactured parts of any size or kind may be produced in the conditicn desired. For instance, on parts of relatively small section, say i or under, in which medium hardness is desired by heat treating, the abnormality would be increased to a relatively high I degreathe manganese and carbon-would be relacondition of abnormality and molybdenum that is responsible for the unusual ductility, toughness and fatigue resistance results obtained, while the hardness, generally considered, is influenced in the regular manner by the carbon and manganese and sometimes silicon.

The molybdenum makes it possible to secure the desired depth of hardness penetration which, as previously stated, may vary'from uniformity throughout from surface to middleor shade off from the surface towardithe middle. The manl and of the following compositions,

ganese, while tending to increase total hardness, and while having some slight effect on depth of hardness, has a tendency to increase outside hardness with inside softness, which means that it Remarks ganeso J: 5 5 scomqocncwncw I P Pinions and rings Pinions and rings Pinions and rings Transmissions Transmissions issions Structural Bolts Pinions and rings Manganese for increasing a cesarean e55 Transmissions. Mn for as 'e message'sa e e a a "s e messa es a5 a: a a a senescence 5';

below. Mn ina'easinkhat 5 dness Mfiigrganese for increasing Mani Molyb- No. Carbon 8811689 8111001: denum Remarks 15 '.65- .90 .35 .25 'Pinionsandrings. Biaddition for hardness 16 .85 1.00 .35 .25 Pinionsandrings. Sleddition (or hardness 17 65 1.10 .35 .25 .Pim'onsandrings. Siaddition for hardness l8 .50 .90 .35 .25 4 Si addition for hardness 19 .50 1.00 .35 .25 Trans. Si addition for hardness 20 -.50 1.10 .35 .25 Alsoiornormalim 21 90 l. 10 25 Normalize 22 .00 1.10 .75 .25 Normalize 515 .657 .66 .27 .26 Structural, parts, water 1 quenched 516 .565 .65 .26 .25 Structural parts, water i quenched 511 .430 1 .00 .24 .25 Structural parts, water quenched 518 .370 .67 .24 .25 Structural parts, water 1 quenched I havev also produced heats with the carbon va- 'rying from .0% to 370% and with the manganese as low 'as- .40% for pieces shading off from ahard surface to a soft but tough core.

I have produced 6 ton electric furnace heats for many purposes in a medium abnormal condition accompanied with the addition of molybdenum and with the carbon at 55%, 55%. 50%, .45% and 40%. Also open hearth heats in these ranges.

I have produced automobile coil springs for independentsuspension of approximately the following analysis: 05% carbon; .80% manganese; .025% each of sulphur and phosphorus; 25% molybdenum; 25% silicon; 5 to 8 or finer grain size; and in an intermediate. condition of abnormality between what I choose to call slight- 1 The point to 1y abnormal and fully abnormal. which abnormality can be carried can readily be determined by experiment. It must stop short of the point where the desired results would not be Obtained. (Generally speaking, abnormality 'should stop short of the disappearance of pearlite.) From this condition of material I produce coil springs which are heated at about 1500? F., quenched in oil and drawn at 800 F. with a resultant Rockwell hardness of 42-40 C These springs 'have anunusual amount of toughness, ductility and fatigue resistance.

For purposes of comparison I have here tabulated the properties of this steel with a steel of comparable analysis in general use for this purpose, the analysis of this latter steel being as follows:

Acid open Oscillations of 3% hearth diacoil springs c -.007 Max. 300,000 Mil-:45 Min. 22,000 mm P --.0s5 Av. 45,000 1 51 -.045

This steel o"'-.05% Max. 580,000 Mn-.80 I L g ro-fig Min. 125,000 30 tests s I0s0 Av. .4o0,000 P -.0s0

I have also produced axle shafts according to my invention which, at the same torsional strength as chrome-nickel and chrome-molybdenum steels, show from two to three times the degree of twist at the breaking point. Comparative results are given in the following table in which the material labeled .Mola is steel of my invention and had the following composition: carbon iron. "I'he'other steel M010 and in the other instance it the i 10 is .1... known"oertain ofthese-condl- .tions will produceiine grain; 'Ih'e'useoi ilnely.

j divided mill scale in a bath oi metalitends'to produce 11, iirie grained condition. It isalso known that aluminum has a decided cilectin producing certain conditions ot-grain'size and abnormality.

I prefer to produce the desired condition-oi abnormality andgrain size through the use oi regular heat treatment. 7 aluminum and molybdenum added to the heats Rear axleehalt test-Model Tamer ii. 8. 512001100 M08. 6 Reg. I n. '1. Men 11. a

-1 1.000 1.2 1.000' 1. 041' 1. 000' 11040 1.042" 1010-100 Smallest dis 1.041 1. 1. 000' 1. 041' 1. 000' 1. 040' 1.042 E. L. inch (actual) 00.100 00,100 00,000 00,000 00.000 00.000 00.000 40 01 00,100 00,100 000 04.000 00.000 04.000 00.000

444 420 010 400 010 000 000 41s 000 0 1 420 002 041 000 4140 .4140 4142 4444 4141 0000 "0000 41111 4040 4142- 4444 --4142 4000 0000 4141 4040 0041 444.0 0041 0040 0000' 4140 4440 0000 4440 0041 0000 0040' 4040 4044 I 0100 4440 0140 0100 0040 44g 440 0000 4440 000a .0001 0000 M1ddle 44 40 0000 4 440 0001 -0000 010a 40.: 40 0000 4440 0001 0000 0000 41 00 40 00 00 40 40 00 01 -00 01 00 00 4040 4141 0101 40 0101 0101 00,00 41 4 42 44 0s 00 40 40 0s 0s 0s 00 00 Outside 40-41 1. 4040 40 2 4444 424 0000 0040 method and-the practice principally vii-11005111 that Iproduce theabnormal steel in tion with molybdenum and a'controlled balance. I or other elements, instead of the normal steel that is commonly accepted. as. that desired. rawterm-silicon) abnormal. 11100 I am also applying the combination 0! abnormality and molybdenum content, together with manganese and as hammer rods, 'dieblocks and other large sections for both heat and normalizing,- 1 that I may use in combination with this abnormal structure, "molybdenum up to about 1.50%,

companied by varyingamounts oi not much over 2.50% to 3.0% i silicon not above about 2.00% and carbon-u to 0001 0 For certain special conditions 'esmay g'o somewhat higher.

Ialso can control, by the proper balance of abnormality and molybdenum with-variation in the other constituents, the depth of hardening to such an extent 011001001 produce very hardening, thorough or complete hardening. or-

any degree of depth hardening between these extremes. r

I produce the steel in electric or open hearth furnaces or by the crucibleor any other materials used and the 011031 additi s a e-made in thesame way as general practice'has-dietated. with respect to'abnormality .itjis-known" there are several ways in which ithas been produced, although it has been the general intention 111' steel .manuiacture to produce-only normal steels for consumption. itdsknow'n an'muntoi the (;'11sually- 101100 suiiicient the 00001 may be that under certainoonditions.

that. i! the the addition oi vanadium and sometimes 0! tungsten may produce abnormality.

silicon to large work. such.

at the proper time and under the proper conditions. which I generaliyadd-at the end or, or toward end of the heat, I produce the bath of metal in the regular manne adding thevarious-eie ments as they are generally added, in the .usual way, and in the oi electric 1111 naoes: I prefer to add thealuminum to the bath while in the furnace after the heat has been This is particularly true 0! the'aluminum 3 01110111000 term-silicon) and about thirty minutes be! ethe heat is poured, and in suiilcient amount and under conditions or temperature anddeoxidation oi the heat, to produce the abnormality that I desire. I have found that the best temperature Xor'theti'me oi the addition 0! the aluminum is Thissometimes'. maybe varied 100' to Run at down without objectionableresults. 10 will be observed that the addition is to'be'usually made 0 0010 00 It, in order to get the best results.

18 8180 to benoted that itfis best t0 empmy the usual. amount-oi dooxidizer '(ierro-silicon). In fact-I preiei' ito go a, little bit-towardthe side in the amount of ierro-silicon-emplo'y'ed and produce a normal steel, which I then change to a controlled condition 0! abno ality by adding -Ihe aluminum is not produces the abnormality but also the line grain structure. For the open hearth, I add; aluminum in the amount. oi about 1 /4 lbs.

addition and' ten. This will producewh'atl term medium.

abnormality, i e., about hall-way between slight abnormality and the. maximum which -I have thus far 100.1104! tobepermis'sible. To decrease or increase the abnormality. the quantity 0! i aluminum 10 reduced or increased. :Thns tarry have iound that the aluminum should not be decreased much. below: 1 lb. perton, or increased ferro-silicon. In this connection it is to be observed that the quantity of ferro-silicon employed is that required for deoxidation plus the additional amount needed to give the desired silicon content in the finished steel.

For the electric furnace I flnd that less aluminum is needed and for medium abnormality I usually add about one pound of aluminum per ton,

the addition being made about thirty minutes before pouring. Y

Of course, for diflerent furnace characteristics, it will be founddesirable to vary the procedure and the amounts somewhat, in order to get the best results.

The outstanding uniformity of the characteristics of my steel is well illustrated in the following impact tests. A standard Izod machine was 1 changed in the following manner: The upper part of the machine was raised approximately 1 so that the edge 01' the impact blade hits 2" above the top of the anvil which grips the test piece. The test pieces were made from the. original size of the spring steel rods (.689 plus or minus .004

.dia.) which were heat treated the same as the springs, i. e., heated to 1600 F., cooled in air for approximately 30 seconds, transferred to a furnace at 1500 F., heated at this temperaturefor thirty minutes, then quenched in oil followed by an 800 F. draw. The pieces were then ground with a grinding wheel wide. The diameter across the groove was .650".

out. In these pieces there was no change in hardness from 500 F.'to 1000 F. draw.

To illustrate the extremely wide range of heat treatment possible with my steel, without detrimental'eifect on the properties, I have made numerous tests with both water and oil quenching from 1400 F. up to 1800 F. with no appreciable effect on the properties or the steel. This is remarkable, particularly with respect to water quenching, as one would normally expect that the range in which detrimental effects are avoided, would be very much less.

In Figure 5 I have reproduced a graph showing the effect on-four different but comparable steels, of temperature on'grain growth. The-first" steel was a standard 1095; the second was amolybdenum steel, normal; the third was a chromevanadium steel; and the fourth is a molybdenum steel of my invention, abnormal. It will be observed that the grain steadily grew in size in the first three steels, whereas in-my steel the grain size remained substantially the same from 1400 to about 1700. v

' Toillustrate how the molybdenum carries in the depth of hardening and how slightly, in my steel; this condition is affected by temperature, I have reproduced in Figure 6 a graph of the depth hardness curves of the fourth steel of Fig- I ure 5. This graph needs no explanation. By

way of comparison, in Figure 7 I have reproduceda graph of depth hardness curves of a standard SAE #1095 electric-steel. It willbe observed how at 1400? the hardness toward the center drops.

f To be a little more specific as to the control of abnormality and grain size in the electric furnace.

The steel is produced in the regular manner with the exception that 'I reduce theferrous oxidewhich is judged either by the appearance and i l %Variition from IV. Max. Hardness Brlncll in. Hardness Brinell Average (Libs. surface center mm. 81111806 center it. lbs.

' Low High M450 1% 401 444 08 444 444 111 12 v 14 71697 109 444 444 102 444 444 105 4 I 3 26469 118 444 444 95 444 444 106 l1 10 26474 129 444 444 103 444 444 113 8 14 25457 120 444 444 90 444 429 101 l2 l9 26580 100 444 444' .92 444 v 444 100 8 ll 25455 100 444 444 87 444 444 97 11 12 $378 104 444 444 87 444 444 92 0 .13 36505 115 444 444 95 444 444 105 9 10 71645 in 444 444 104 444 444 112 8 7 35394 157 444 444 118 444 444 130 9 21 35350 115 444 444 84 444 444 06 12 2) 71765 109 444 444 90 444 444' 97 7 13 Average-9%, 13%. I

Figures 3 and 4showing tw'o pieces of spring steel analysis, the composition of which was carbon .65%; manganese .80%: mo y d 8 con .25%; and the balance iron with the usual traces of sulphur and phosphorus. These pieces were 3" square. One was normalized at 1550 F. and the other at 1650. 1". It will be seen that in both pieces the hardness was uniform throughaction of the sampled slag, or by a'quantitative estimation of the ferrous, oxide in the bath-by the addition to the bath of first, term-manganese, 1

followed by ferro-silicon, after which I add about 1 pound to 1 pounds of aluminum per ton of steel which I 'hould be approximately 2800 F. when poured. In the case of electric furnace heats, the aluminum isadded to the bath about thirty minutes before pouring, by attaching pig or cast aluminum in forms to a bar and pushing it through the slag and below the surface of the steel until the aluminum is completely melted. The reaction that occurs is between the aluminum and any ferrous oxide that remains and also with the other oxides that are'present wherein the amnity of the metal for oxygen is less than that of aluminum for the same oxygen, andthis, reaction that occurs I believe to be the formation of alumina under a condition that aflords ex-- or larger mounts of aluminum wherein solution of aluminum instead of dispersion of alumina would be eilected.

'5 I can also produce similar results from electric furnace'he'ats by adding the aluminum in the ladle, harder to control.

although the'conditions are somewhat lows: The electric furnace heat is carried through the regular slagging and the addition of ferromanganese is made and sometimes but not always, enough ferro-silicon is added to the bath suflicientto kill or deoxidi'ze the heat, but no excess is used. In general it would be betterto leave the heat under-killed. The analyses, except for silicon, are balanced, and the heat poured at about 2800 F. As the first. metal hits the ladle a part of the ferro-silicon necessary to bring the heat to the desired silicon analysis and the oxidation condition is added and then from 1 to 1%, pounds of aluminum per ton is added, after which the remainder of the ferro-silicon is. added and the pouring of the heat finished.

With respect to open hearth furnace, I have only added the aluminum to the steel in the ladle,

although I can use another method of adding the aluminum as hereinafter shown. After the heat has been properly melted and carried through as any regular heat of open hearth steel, the analyses, with the exception of silicon, are balanced and the heat adjusted to a temperature of approximately 2800 F. The heat is then poured. After the pouring starts, I add part of the ferrosilicon necessary to balance the silicon analysis and then add the aluminum, about 1% pounds per ton, then the remainder of the ferro-silicon and continue the pouring to the end.

If the steel is in such a condition at the time of the addition of the aluminum, or the amount of aluminum is not in the right amount so that the solution occurs instead of thorough alumina dispersion, then the proper grain size will not be produced and the steel may not be abnormal but normal, which latter is the conditionI wish to avoid. If solution occurs instead of dispersion, then there is a tendency toward normality and large grain.

As an alternative method for adding the aluminum to the open hearth furnace, I can embody a method similar to what I use in the electric furnace, 'namelyjadding the ferro-silicon following the addition of ferro-manganese until the heat is killed to the right degree for adding aluminum, about 1% to 1 pounds per ton, to the bath by attaching a pig or casting of aluminum to a heavy rod and pushing one or more of such castings quickly through the slag and down through and nearly to the bottom of the-bath. This operation may either be performed by hand or by a mechanical 6. e made to operate through the doors or through the top of the furnace. It is sometimes necessary to add in the ladle some ferro-silicon to complete the required silicon analysis.

I find that very satisfactory steel can be produced with the following analysis: carbon from about .60% to about 170%; manganese from about 110% to about 90%; silicon from about 20% to about 30%; molybdenum from about .20% to .30'% and the balance iron with the usual traces of sulphur and phosph rus.

I have also found it useful to operate at about the following range: carbon from about .15% to aboutv 2.0%; manganese from about 30% to about 3.0%; silicon from about .15% to 2.50%:

The method then is as fol-.

molybdenum from about and the balance iron with the usual traces of sulphur andphosphorus.

I have also made heats with other elements in addition to the molybdenum. For example:

Made with aluminum, silicon, iron alloy instead oi ierrosillcon and aluminum.

It is to be understood that I do not limit myself strictly to the elements and percentages given and that-the claims are not to be construed as excluding the range of equivalents for obtaining the same results to which I may be entitled. The degree of abnormality should be at least suffi- 20% to .about 1.50%;

Percent Percent Percent cient to give pronounced increase in properties as compared with a normal steel of comparable analysis. can be readily determined forany given alloy by experiment. The upper limit of degree of abnormality has been elsewhere ven.

This is a continuation in part of my applications .Serial Nos. 704,517, filed December 29,1933 and 715,492, filed March 14, 1934.

WhatI claim is:- 1. An alloy steel which is abnormal 'or characterized by a condition of appreciable dispersion or divorcement of cementite and includes the following ingredients substantially in the amounts specified: 4 Per cent Carbon from.. .15 to 2.00 Manganese from .30 to 3.00 Molybdenum from .20 to 1.50

Iron from. 99.20 to 91.00

said steel being characterized by a high degree of ductility, toughness and resistance to shock and fatigue.

2. An alloy steel which is abnormal or characterized by a condition of appreciable dispersion or divorcement of cementite and includes the following ingredients substantially in the amounts specified:

h Per cent Carbonfrom. .15to 2.00 Manganese from .30 to 3.00 Silicon from .15 to 2.50 Molybdenum from., .20 to 1.50

Iron 4 from. 99.20 to 91.00

said steel being characterized by a high degree of ductility, toughness and resistance to shockand fatigue.

3. An alloy steel which is abnormal or characterized by a condition of appreciable dispersion or-divorcement of cementite and includes the fol- Per cent Carbon from. .60 to .70 Manganese from .70 to .90 Silicon from; .20 to .30 Molybdenum from .20 to .30

' Iron from 98.60 to 97.80

lowing ingredients substantially in the amounts specified: v

Per cent Carbon from. .60 to .70 Manganese from"-.. .70to .90 Molybdenum from .20 to .30 Iron Irom 98.60 15097.80

said steel being characterized by a high degree of ductility, toughness and resistance to shock and fatigue.

4. An alloy steel which is abnormal or characterized by a condition or appreciable dispersion or divorcement of cementite and includes the following ingredients substantially in the amounts specified:

said steel being characterized by a high degree-o1 ductility, toughness and resistance to shock and fatigue.

5. An alloy steel which is abnormal or char-' acterized by a condition of appreciable dispersion or divorcement of cemen'tite and comprises the r following ingredients substantially in the amounts specified:

Per cent Carbon .65 Manganese .80 Molybdenum ,25

Iron with traces of impurities 98.30

Leeaeos' Percent Carb n .65 Manganese .80 Silicon .25 Molybdenum .25 Iron with traces of impurities 98.05

said steel being characterized by a high degree of ductility, toughness and'resistance to shock and fatigue. -7. An alloy steel which is abnormal or characterized by a condition oi. appreciable dispersion or divorcement oi cementite; which is also characterized by a grain size at least as fine as from #5 to #8 of the A. S. T. M. chart; and includes the following ingredients substantially in the amounts Per cent Carbon from. .15to 2.00 Manganese from .30t0 3.00 Molybdenum from .20t0 -1.50 Iron from. 99.20to91.00

said Sh a being characterized .by a high degree or ductility, toughness and resistance to shock and fatigue.

- CHILD HAROLD WILLS.

. Certificate of Correction Patent No; 1,992,905. Fehruary 26, 1935 CHILD HAROLD WILLS It is hereby certified that errors appear in the printed specification of the abovenumbered patent requiring correction as follows: Page 2, second column, line 28, for 40% read 40%; and line 33, after the semicolon, for 25% read 25% page3, firstcolumn, in the table under the boxed heading Material the third entry should read E. L. inch# (actual) and the fifth entry Max. inch# (actual) instead of as shown; same table, under the heading Specification first entry, rea'd 1.3754 1/32 instead of 1.375- 132 page 4, first column, line 3, for labl'e read ladle; andpage 5, second column, line 26, the printed mattei' in small ty'pe relates only to the last mentioned steel of the table; and that the'said Letters Patent should be read with these corrections therein that the same ma. conform to the record of the case in the Patent Office.

Signed and sealed this 23 day of April, A. D. 1935.

[SEAL] A. LESLIE FRAZER,-

Acting Patents. 

